The present invention relates broadly to the field of vision testing and more particularly to apparatus for determination of potential retinal acuity in the human eye in the presence of opacities as frequently caused by cataracts and the like.
It is clinically important for the ophthalmologist to determine the potential visual acuity of the retina in comparison to the existing or actual visual acuity in patients with corneal disease, cataracts, or other diseases of the eye causing opacities or irregularity of the optical media. The determination as to whether or not surgery is indicated in such situations will depend largely on the improvement in the visual acuity that might reasonably be expected with such surgery. It is not infrequent for a patient to have 20/200 vision coexisting with a cataract and macular changes such as drusen or pigment epithelial changes. Frequently, the cataract that exists does not, to the ophthalmologist, appear dense enough to account for the visual loss and therefore there is always concern about significant posterior disease. For these reasons, the determination of the potential retinal acuity of the patient in the presence of the media opacities is quite important to the ocular surgeon.